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Bagneux, France

Pecker A.,Geodynamique et Structure | Pecker A.,ParisTech National School of Bridges and Roads
Geotechnical, Geological and Earthquake Engineering | Year: 2015

The topic of this paper is to illustrate on a real project one aspect of soil structure interaction for a piled foundation. Kinematic interaction is well recognized as being the cause of the development of significant internal forces in the piles under seismic loading. Another aspect of kinematic interaction which is often overlooked is the modification of the effective foundation input motion. As shown in the paper such an effect may however be of primary importance. © The Author(s) 2015.

Scotta R.,University of Padua | Giorgi P.,University of Padua | Tesser L.,Geodynamique et Structure | Talledo D.A.,IUAV University of Venice
11th World Congress on Computational Mechanics, WCCM 2014, 5th European Conference on Computational Mechanics, ECCM 2014 and 6th European Conference on Computational Fluid Dynamics, ECFD 2014 | Year: 2014

A numerical model for the nonlinear analysis of R/C shear walls under cyclic seismic loadings has been proposed by some of the authors. It is here validated by comparison with three experimental tests taken from literature on R/C complex shear walls. The finite element numerical models consider both in-plane loaded membrane elements and out-of-plane loaded plate elements. Reinforcing bars are modelled as multiple smeared steel layers for which uniaxial stress-strain relation with isotropic hardening according to the Menegotto-Pinto constitutive model was adopted. The concrete material description is based on continuum damage mechanics and uses two independent scalar damage parameters to describe inelastic response of the material. At this stage of the research the bond-slip between concrete and rebars is not taken into account. Two of the experimental tests considered for the validation were conducted at the NEES MUST-SIM Facility - University of Illinois and concern both planar and coupled complex wall systems. The third experimental program was conducted at ELSA Laboratory (JRC Ispra) within the framework of TMR-ICONS TOPIC 5 program on an U-shaped wall cyclically loaded along two orthogonal directions. All tests were carried out in quasi-static conditions. The good fitting of the numerical results with the experimental ones demonstrates the robustness and efficacy of the proposed numerical model in reproducing the cyclic behaviour of R/C members on both two-dimensional and three-dimensional problems.

Chenaf N.,Laboratoire Central des Points et Chaussees | Chazelas J.-L.,Laboratoire Central des Points et Chaussees | Escoffier S.,Laboratoire Central des Points et Chaussees | Pecker A.,Geodynamique et Structure
International Journal of Physical Modelling in Geotechnics | Year: 2012

Inertial and kinematic soil interactions with a single pile are studied through reduced-scale models in the centrifuge. The physical model consists of an aluminium pile rigidly connected to a stiff cap and embedded into dry and dense Fontainebleau sand. The inertial interaction is observed in the response to an impact on the soil-pile-cap system, whereas the kinematic interaction is observed in the response of the soil-pile system subjected to a harmonic seismic event. The same approach was applied to the combination of both interactions, except that the system employed consisted of the complete soil-pile-cap set. This paper describes the set-up of these experiments as well as the various responses in terms of bending moments, soil acceleration, subgrade reaction p and pile lateral displacement y.

Figini R.,ENEL S.p.A | Paolucci R.,Polytechnic of Milan | Chatzigogos C.,Geodynamique et Structure
Earthquake Engineering and Structural Dynamics | Year: 2012

In this paper, different formulations of a macro-element model for non-linear dynamic soil-structure interaction analyses of structures lying on shallow foundations are first reviewed, and secondly, a novel formulation is introduced, which combines some of the characteristics of previous approaches with several additional features. This macro-element allows one to model soil-footing geometric (uplift) and material (soil plasticity) non-linearities that are coupled through a stiffness degradation model. Footing uplift is introduced by a simple non-linear elastic model based on the concept of effective foundation width, whereas soil plasticity is treated by means of a bounding surface approach in which a vertical load mapping rule is implemented. This mapping is particularly suited for the seismic loading case for which the proposed model has been conceived. The new macro-element is subsequently validated using cyclic and dynamic large-scale laboratory tests of shallow foundations on dense sand, namely: the TRISEE cyclic tests, the Public Works Research Institute and CAMUS IV shaking table tests. Based on this comprehensive validation process against a set of independent experimental results, a unique set of macro-element parameters for shallow foundations on dense sand is proposed, which can be used to perform predictive analyses by means of the present model. © 2011 John Wiley & Sons, Ltd.

Fernandez C.,PST Innovation | Bourgouin L.,PST Innovation | Riegert F.,6 rue Raoul Nordling | Pecker A.,Geodynamique et Structure
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2012

At CRIGEN, the GDF SUEZ research center for gas and new energies, a project on risk management on gas infrastructures (MARTHO project) is aimed, among other goals, at protecting the pipelines against external aggressions such as vibrations. Over the past few years, extensive construction of wind turbines has taken place all around the world in areas where many steel pipelines are already buried. The possible fall of these heavy machines may induce damageable vibrations to the pipeline. The common threshold used by the industry, established by the American Gas Association, is stated1 at PPV ≤ 50 mm.s-1. A more accurate and less conservative model of vibration propagation has been developed and validated by extensive field measurements coupled with a nonlinear 2D-finite element model for the soil. An experimental soil characterization through MASW tests coupled with vibration measurements was performed in a representative soil. As a result, safety distances between wind turbines and pipelines were considerably shortened compared to the previous model. The updated model is now part of the RAMCES software which has been developed for more than a decade at CRIGEN and is widely used in France by transmission operators. Copyright © 2012 by ASME.

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